求和,1/4-1/8+1/16-1/32+.-1/1024
问题描述:
求和,1/4-1/8+1/16-1/32+.-1/1024
急
答
等比数列求和
Sn=a1(1-q^n)/(1-q) =(a1-an×q)/(1-q) (q≠1)
公比为(-1/2
Sn=(1/4)*(1-(-1/2)^99)/(1-(-1/2))